STUDY Why Marijuana Users Never Fatally Overdose

Scientists have discovered a molecule in the brain that may limit the effects of too much cannabis.

Marijuana has never been linked to an overdose death, and new findings may explain why.

Published in the journal Science, French researchers have identified a natural hormone that reverses marijuana intoxication in rats.

In an interview with WebMD, study author Dr. Pier Vincenzo Piazza explained that rats exposed to THC showed a dramatic rise in a brain hormone called pregnenolone. The hormone also seemed to prevent marijuana’s intoxicating effects.

“When the brain is stimulated by high doses of THC, it produces pregnenolone – a 3,000 percent increase – that inhibits the effects of THC.”

But the study, originally meant for developing a treatment for cannabis addiction, has been met with different interpretations.

While the authors say that an addiction treatment based on pregnenolone could soon be tested in humans, others believe the study explains how the brain protects itself from a marijuana overdose.

By binding to cannabinoid receptors, THC triggers the release of pregnenolone, which in turn weakens THC’s action on the receptors – a negative feedback loop that could prevent marijuana users from getting too high.

Considering the low rates of cannabis addiction, Mitch Earleywine, a professor of psychology at the University at Albany, SUNY, adds that a drug for cannabis abuse may not even be necessary.